This was one of the first teams I made after coming back to Pokemon, and it's been working well for me so far. I have a bit of trouble with Blissey, the Rotoms and the odd steel type.
Anyhow, here's the team:
Boom#1
Lead Azelf@Focus Sash:
Ability:Levitate | Nature:Naive
4 HP/252Atk/252Speed
-Taunt
-Fire Blast
-Explosion
-Psychic
Azelf can quickly kill most non-scarfed offensive leads, and taunts the walling/bulky ones. It then explodes, netting its second kill if it was an offensive lead, or switches out to be used to stop a threatening sweep or a pokemon that walls too much of my team.It's a useful flying fairy, as explode lets me stop any potential sweep as soon as it starts. Although useful for blocking ground moves, I am often forced to explode as soon as SR is set up.
Special Wall and General Hit Absorber
Celebi@Leftovers
Ability:Natural Cure | Nature: Modest
6 Def/252HP/252Sp.Def
-Thunder Wave
-Recover
-Grass Knot
-Earth Power
This green fairy can handle most supereffective hits, physical and special. Usually I thunder wave on their first hit, and I'll take 60% from their pursuit or fire punch, or 30% if it's an ice beam, then proceed to recover until paralysis stops them from hitting and throw a generally super-effective earth power or grass knot back, getting a kill. U-Turn and Megahorn are certain killers though, so they're avoided as much as possible. I love this guy because they'll switch in counters, and I'll just kill them in five turns or so. It has a bit of trouble with special walls, like blissey which I can only thunderwave, restore myself to full health, then switch out.
Boom #2 Physical Wall and Support
Metagross@Leftovers
Ability: Clearbody | Nature: Lonely
6 Sp.Def/252HP/252Def
-Reflect
-Stealth Rock
-Meteor Mash
-Explosion
A common switch in to ambipom leads or scizors, I'll set up reflect and stealth rock. Depending on their switch in I often go to Gyarados to set up with a DD or explode if it's a threat to any of my offence. I like how it can take an earthquake for around 40%, Reflect, take another for 20%, Stealth rock, then boom for a free switch to gyara. Unlike with electrode, my booms are rarely predicted, however the occasional mixmence or nape will ruin my strategy, as I'll reflect after seeing a couple of physical moves, then get killed by the flamethrower/fireblast. Works well with Heatran who sucks up the flamethrowers like milkshakes.
Physical Sweeper and someone to take my ground weakness that a lot of my team has
Gyarados@Life Orb
Ability: Intimidate | Nature: Jolly
4 HP/252Atk/252Speed
-Dragon Dance
-Waterfall
-Earthquake
-Ice Fang
Generally the earliest member of my offence to get used, one DD then into the attack. It usually switches in from earthquakes, especially from Swamperts. I chose ice fang over stone edge as it OHKO's Salamence and Gliscor, and I have electrode or celebi to T-bolt or T-wave the less common opposing Gyarados.Life orb and SR damage severely sap my health usually giving me only 2 switch ins, so other item suggestions are welcome.
Boom #3, Special Sweeper
Heatran@Choice Scarf
Ability: Flash Fire | Nature: Naive
4HP/252Sp.Atk/252Speed
-Explosion
-HP Ice
-Fire Blast
-Earth Power
My answer to rotoaster, and my special sweeper as soon as electrode explodes on Blissey. Absorbs plenty of attacks with its steel resist and flash fire, but is primarily used in the latter stages of the game when I've got two or three pokes left, letting me go in for a hit and back out. I often am left with a Heatran on 20% against their last full health poke, and a nice explode finishes them off. It's annoying however when I get stuck 1vs3 locked into a move that won't kill them all. I chose HP Ice over HP grass for the ground/flying or ground/dragons that are a greater threat to Heatran and the team than Swampert, just because I have Gyarados and Celebi to deal with it. I ran naive just to beat the other scarftrans, and so I don't put a dent in my explode power if I need it.
Late game sweeper
Lucario@Life Orb
Ability:Inner Focus | Nature: Jolly
252Atk/252Speed/4HP
-Swords Dance
-ExtremeSpeed
-Close Combat
-Crunch
Swords dances up and sweeps away. Used to be focus sash lucario, but changed on recommendation and after a bit of testing. Close combat kills everything that crunch/ES can't. Max speed is to outspeed other lucarios. Although it adds a ground weakness to the team, two immunities and a resist balance it out. Has been on my team forever, as a sub/salac, focus sash and now life orb variant. Often used as a blissey detterrent, it is very reliable as its only weaknesses are well covered.
At a glance:
Anyhow, here's the team:

Boom#1
Lead Azelf@Focus Sash:
Ability:Levitate | Nature:Naive
4 HP/252Atk/252Speed
-Taunt
-Fire Blast
-Explosion
-Psychic
Azelf can quickly kill most non-scarfed offensive leads, and taunts the walling/bulky ones. It then explodes, netting its second kill if it was an offensive lead, or switches out to be used to stop a threatening sweep or a pokemon that walls too much of my team.It's a useful flying fairy, as explode lets me stop any potential sweep as soon as it starts. Although useful for blocking ground moves, I am often forced to explode as soon as SR is set up.

Special Wall and General Hit Absorber
Celebi@Leftovers
Ability:Natural Cure | Nature: Modest
6 Def/252HP/252Sp.Def
-Thunder Wave
-Recover
-Grass Knot
-Earth Power
This green fairy can handle most supereffective hits, physical and special. Usually I thunder wave on their first hit, and I'll take 60% from their pursuit or fire punch, or 30% if it's an ice beam, then proceed to recover until paralysis stops them from hitting and throw a generally super-effective earth power or grass knot back, getting a kill. U-Turn and Megahorn are certain killers though, so they're avoided as much as possible. I love this guy because they'll switch in counters, and I'll just kill them in five turns or so. It has a bit of trouble with special walls, like blissey which I can only thunderwave, restore myself to full health, then switch out.

Boom #2 Physical Wall and Support
Metagross@Leftovers
Ability: Clearbody | Nature: Lonely
6 Sp.Def/252HP/252Def
-Reflect
-Stealth Rock
-Meteor Mash
-Explosion
A common switch in to ambipom leads or scizors, I'll set up reflect and stealth rock. Depending on their switch in I often go to Gyarados to set up with a DD or explode if it's a threat to any of my offence. I like how it can take an earthquake for around 40%, Reflect, take another for 20%, Stealth rock, then boom for a free switch to gyara. Unlike with electrode, my booms are rarely predicted, however the occasional mixmence or nape will ruin my strategy, as I'll reflect after seeing a couple of physical moves, then get killed by the flamethrower/fireblast. Works well with Heatran who sucks up the flamethrowers like milkshakes.

Physical Sweeper and someone to take my ground weakness that a lot of my team has
Gyarados@Life Orb
Ability: Intimidate | Nature: Jolly
4 HP/252Atk/252Speed
-Dragon Dance
-Waterfall
-Earthquake
-Ice Fang
Generally the earliest member of my offence to get used, one DD then into the attack. It usually switches in from earthquakes, especially from Swamperts. I chose ice fang over stone edge as it OHKO's Salamence and Gliscor, and I have electrode or celebi to T-bolt or T-wave the less common opposing Gyarados.Life orb and SR damage severely sap my health usually giving me only 2 switch ins, so other item suggestions are welcome.

Boom #3, Special Sweeper
Heatran@Choice Scarf
Ability: Flash Fire | Nature: Naive
4HP/252Sp.Atk/252Speed
-Explosion
-HP Ice
-Fire Blast
-Earth Power
My answer to rotoaster, and my special sweeper as soon as electrode explodes on Blissey. Absorbs plenty of attacks with its steel resist and flash fire, but is primarily used in the latter stages of the game when I've got two or three pokes left, letting me go in for a hit and back out. I often am left with a Heatran on 20% against their last full health poke, and a nice explode finishes them off. It's annoying however when I get stuck 1vs3 locked into a move that won't kill them all. I chose HP Ice over HP grass for the ground/flying or ground/dragons that are a greater threat to Heatran and the team than Swampert, just because I have Gyarados and Celebi to deal with it. I ran naive just to beat the other scarftrans, and so I don't put a dent in my explode power if I need it.

Late game sweeper
Lucario@Life Orb
Ability:Inner Focus | Nature: Jolly
252Atk/252Speed/4HP
-Swords Dance
-ExtremeSpeed
-Close Combat
-Crunch
Swords dances up and sweeps away. Used to be focus sash lucario, but changed on recommendation and after a bit of testing. Close combat kills everything that crunch/ES can't. Max speed is to outspeed other lucarios. Although it adds a ground weakness to the team, two immunities and a resist balance it out. Has been on my team forever, as a sub/salac, focus sash and now life orb variant. Often used as a blissey detterrent, it is very reliable as its only weaknesses are well covered.
At a glance:





